Efficient farm layout benefits weed control
Succession planning for a farming business is an opportunity to embrace the next generation’s new ideas and energy while building on the foundational work initiated by earlier generations.
As Kim and Michelle Slarke transition their business into the hands of their sons, Jamie and Harrison and their families, they are transforming how they farm and manage weeds on their 8800 ha aggregation at Lake Grace, WA.
Since taking over the family farm in 1988, Kim and Michelle have introduced minimum till, controlled traffic, prescription soil mapping, and variable rate application of lime and fertiliser. Most recently, they have wound up their sheep enterprise and implemented block farming, where blocks of up to 2000 ha are sown to a single crop species. This has involved a considerable shift in how they maximise machinery efficiencies and streamline operations like chemical applications.
Since 2018, break crops have replaced the 25 per cent of the rotation that had previously been sown pasture for the sheep. A typical rotation now is a legume or canola crop followed by two to three cereal crops, then back to canola or perhaps oaten hay, depending on the weed burden in each block.
Block farming has changed the way they farm
The block farming layout allows the Slarkes to complete major operations like seeding, spraying and harvesting without moving machinery back and forth.
The main infrastructure changes have been the removal of fences and lone, stressed trees in favour of protecting the remnant vegetation areas. They have been pleased with how the unfenced shade areas on the edges and within the paddocks are thriving without grazing pressure.
Removing the fence lines has effectively removed one of the farm’s primary sources of weed seeds and herbicide resistance. No longer needing to manage these ‘weed nurseries’ has been a significant benefit of changing to block farming.
Over time, the legacy effect of the old fence lines within the blocks is reduced as they apply multiple in-crop strategies to keep running down the weed seed bank.
“In the first few years, we would patch out some of those fence lines if the weed numbers were high, using a suitable in-crop herbicide or even spraying out the crop along the old fence line if necessary,” he says. “The aim is to pull those weed numbers down until it is impossible to identify the old fence line due to a higher weed burden.”
Spray efficiently and effectively
As part of their block farming layout, the Slarkes have created a network of gravelled roads that run along both ends of each block. When spraying, they park the batching truck on the gravel road at one end of the paddock and move it along as the sprayer progresses.
The batching station includes a truck carrying a 28,000 L water tank and a trailer carrying the required chemicals in bulk containers. This setup has vastly reduced the time taken to refill the sprayer, keeping it in the paddock for longer within the narrow windows for spraying, and reduced the physical handling of chemicals.
The Slarkes run an Agrifac self-propelled boom spray with many more spray options than their previous sprayer – enabling them to get better target coverage when applying herbicides. While they have always backed into corners on the outside lap of a paddock, the new boom spray also has turn compensation, ensuring accurate application of herbicides at full rate. They use water-sensitive paper to check spray quality to ensure the sprayer set-up achieves the coverage required for each application. The ability to control individual nozzles provides multiple options for optimal application.
The Slarkes use a standard water rate of 80 L/ha and feel they are achieving effective control with those rates with that boom. They drop back to 60 L/ha for summer spraying if the targets are larger.
The Slarkes don’t map their weeds besides noting where the weed patches are at harvest. Kim says they have decided not to patch-manage weeds in their blocks, except along old fence lines. They prefer to apply the same treatment across the whole block to ensure no small patches or individual weeds are missed.
Their Agrifac sprayer can have weed detection cameras added for automated spot-spraying, but at this point, the Slarkes can’t justify the cost on their existing machine, even though there would likely be savings in herbicide costs, particularly with their summer spraying program.
Being very wary of spray drift potential, they choose appropriate nozzles and set the pressure carefully for each job. Everyone operating the boom is aware of the risks, and if there’s any doubt, they stop spraying and return when the conditions are suitable. They plan their spray applications carefully, taking into account the wind direction and speed and where crops are out of the ground.
The Slarke family implement all of the WeedSmart Big 6 tactics in their integrated weed management program to minimise the impact of herbicide resistance on their farming business.
The WeedSmart Big 6 strategy embraces herbicide and non-herbicide weed control tactics to keep weed numbers low in cropping systems.
